Are You Curious?
by It'sMe-AshleyMarie
Summary: Kate's got an interesting read in her hands but refuses to tell Castle what it is. So, it's up to him to figure it out, and he's in for an interesting turn of events when he discovers what it is.
1. Chapter 1

Are You Curious?

It could be considered a normal day because Castle's curiosity was running on overdrive, but today, he was even more intent than ever on solving the mystery that was Kate Beckett. He came home from a book meeting one night and found Kate lying on their bed completely immersed in a book, so he knocked on the door as not to scare her too much.

"Hey, come have some wine?" Kate looked up and placed her finger in the book to mark her page.

"Yeah. Just give me one second."

"Of course. What are you reading over there?" Kate held the book to her chest before Castle could see, careful to conceal the title.

"Oh, nothing." Kate gave her husband a kiss on the cheek and hurried into the bathroom with the book before Castle could follow her. "Be out in a minute!" Castle stood in the middle of the bedroom puzzled but shook off his suspicion for the time being to relax and have a glass of wine with his newly wed partner.

Wine in their systems, the couple snuggled under the covers together, kissing each other sweetly and talking about random things, still in the bliss of their newlywed state. After a particularly heated make-out session, Castle laced his fingers in Kate's and stared at her seriously.

"Kate, you promised me no more secrets, right?" She nodded. "So," Castle kissed her and pulled her to his chest. "I think that you not telling me what very interesting book you're reading counts as withholding information, don't you?" Kate rolled her eyes and turned her back to Castle.

"You're not going to force it out of me, Castle. I make people crack under pressure, but I personally don't."

"We'll just see about that, won't we?" Castle immediately moved his hand to Kate's side and tickled the area just above her hip, the spot she couldn't stand being touched. Kate laughed and squirmed under her husband trapping her, but Castle refused to let up. "Come on, Kate. Raise your white flag and surrender." Castle straddled Kate and held her wrists in his hand to keep her still, but Kate wouldn't give up her fight.

"You wish." Castle ravished her neck and smirked at her before releasing her and turning over to sleep again.

"Oh, I'll get it out of you, Kate, and I won't stop until I do. Knowing that, sweet dreams." He kissed her on the head and drifted off, and Kate's dreams were pleasant, however, anything but sweet.

* * *

Back at the precinct the next day, the couple looked fairly normal to the untrained eye, but the two of them knew the subtle differences in each other's behavior. After Kate had met with Captain Gates about the case, she ran in to Castle in the break room to grab her cup of coffee.

"Beckett, could you go check with Ryan and Esposito and see if we have anything more on our victim?"

"Yes, Sir." It didn't register what Kate had just said until Castle cleared his throat and stared quizzically at her. _Shit._ "I was meeting with Gates. Force of habit," she eventually stuttered, and she made a hurried and unpolished exit out the door. Once again, Castle stood confused but couldn't shake the feeling that something was different with Kate, something she wasn't telling him . . . Yet.

* * *

It happened again later that day, and Castle didn't bother to ask, blaming it on her "force of habit" again. As much as the title boosted Castle's ego, it wasn't like Kate to think of him as an authority figure because the roles would usually be reversed. He had to get to the bottom of whatever this was.

Kate hinted at rougher sex that night, and Castle, of course, always aimed to please; he fulfilled her desire to his finest, assuming a more aggressive role easier than they both thought he would. She thoroughly enjoyed herself and let go of her inhibitions, even as Castle forced her arms over her head and fucked her through her orgasms without stopping. The two fell into a boneless heap on the bed, and Kate denied Castle the name of the mysterious book once again after he asked. _New tactic_ , he thought, and he dreamt about all the ways he could make her confess.

* * *

"Babe, I have to stay late at the precinct and finish some paperwork. I'm sorry." _Perfect timing._ He couldn't say that, so he covered it up with a sincere apology.

"No, don't be. I'll just see you when you get home then. Love you." Castle kissed Kate on the cheek on the way out.

"Love you too." She blew him one more kiss in the elevator, which he accepted tenderly, but as soon as the elevator doors closed, he was ready to find this damn book and solve the case of his own.

Castle searched the entire living room where he found Kate reading the evening before but couldn't find a book similar to the one he had seen. A dark cover, though he couldn't differentiate navy or black, about an inch thick, and something silver on the front. He couldn't make out any words when he last saw it, so the search would take longer than expected. Thank God he found an enticing clue on the coffee table where Kate's wine sat the night before. His gray silk tie lay on the table, but it wasn't the tie he wore yesterday. Castle used his detective skills he picked up from his wife and considered it evidence until proved inadmissible later. However, it wasn't just the tie that was cryptic; Kate wrote him a note on a small card that made him seriously questioning and turned on. _"Are you curious?"_

Hell yeah he was. Suddenly, he remembered that he left before Kate this morning, which was odd because Kate was always early to work, so, in reality, the book could be anywhere in the damned loft. Upon entering his office, he saw the black mask that Beckett wore to a masquerade on a case placed neatly on the chair that wasn't there when he left. Carefully placed next to the mask was another note in her handwriting. _"We aim to please."_ Had someone broken in during the day, and why the hell would that mask just be there?

Having no luck in the office, Castle made his way into his and Kate's bedroom but not before catching a pair of handcuffs hanging on the doorknob and a note attached to some curling ribbon with another message. _"Come out and play."_ Kinky sex? Sure, they had done that before, and both Kate and Castle had been on the receiving end of pleasure inside the cuffs, but she had outright asked for that beforehand, so what was she trying to keep hidden? What innermost desire could she not allow herself to come out and say?

Bingo. As soon as Castle opened the door, a dark book sat in the middle of the bed with a final card atop it, this one inside an envelope with the same neat script across the small page. _"There's a very fine line between_ _ **pleasure**_ _and_ _ **pain**_ _. They are two sides of the same coin, one not existing without the other."_ Castle read the card multiple times to fully understand the significance of the quote but could not do so without the context of the book. He examined the book, flipping it over to reveal the title: _Fifty Shades of Grey_ by E.L. James.

So that's what she was keeping from him the whole time? Kate had been so secretive about it before but set him up to find it days after he couldn't solve her mystery once again. He realized why the two words of the quote were emphasized and what Kate wanted him to do. It's why she said she was "staying late" at work; she wanted this, and she wanted it bad. Castle was not used to being the leader and the one in control, but if it made Kate happy, he would do his best to satisfy her need. Thank God Martha and Alexis had made a weekend trip to the Hamptons!

Castle flipped through the book and found that certain pages and phrases were either doggy-eared or underlined with little notes in the margins, probably for his ease. She basically gave him the instruction manual on how and what he should do to her and for her. While his research in BDSM was minimal at best, he knew a little of what was to be expected and recognized certain terms off the bat and continued to submerge into this new fantastical world. Eagerly, he studied the "manual," and while he critiqued its less than eloquent writing style in comparison to his own, it gave him a pretty clear idea of what Kate wanted. The mantra he had to follow would be to let her ultimate pleasure guide him, and it would unlock everything he needed to give her, for this was all about her. Tonight, he would give her exactly what she had been yearning for, and he would give it to her right.

* * *

Kate came home about three hours after Castle and instantly felt something different. A chill raced down her spine, but the air suffocated her. Something out of the ordinary was going on, and she wasn't quite sure what to expect. She called out softly for her husband, but he didn't respond, so Kate took a look around the rooms in the loft to find him and found his tie missing from the coffee table where she had it this morning. If he wasn't in the living room, he'd probably be writing in his office; he wasn't and the mask she planted there was gone. So, drawing conclusions, he must be in their bedroom. Before she entered, she noticed the cuffs were no longer hanging on the knob, and she carefully entered the bedroom.

Silence. Worse than that, darkness. Kate couldn't see anything that wasn't right in front of her, and Castle's name left her lips as a quivering whisper.

Suddenly, something pulled her back and held her tight, and Kate gasped in shock more than fear as she felt the familiar hands of her lover against her stomach. This was her Castle, but something changed about his touch in mere hours that she couldn't quite comprehend until he spoke hotly against the shell of her ear.

"When you're in here, you are completely mine to do with as I see fit. Do you understand?" Immediately, Kate knew the scenario in place because Castle had just quoted _the_ book, and since her clues were missing, he had discovered her secret little desire. Kate's chest shuddered with the new and intense sound of her lover's commanding voice, a low and smooth baritone with just a hint of gruff that could effortlessly send her over the edge. She never heard him speak like that except in the throes of intense pleasure, but Kate could get off on his voice alone like that. Something about it excited and scared her at the same time, and yet their perfect contradiction was a most beautiful thing.

As she had never truly before, Kate Beckett took a leap of faith and submitted to Richard Castle.

"Yes, Sir."


	2. Chapter 2

Are You Curious?

Standing in the threshold of the darkened bedroom, Kate drew in a shaky breath and forced herself to let go of the tension she was holding. Though this was new for the both of them, she trusted Rick and knew that he would keep her safe because, hell, he was just as nervous as she was.

"What's your safe word, Kate?"

"Red."

"And if you need to slow down?"

"Yellow." Castle rewarded her with a kiss behind the ear and his gentle caress down her arms.

"Good girl. Strip for me." Castle circled around her and stood in front of her waiting for her to make her move. "Don't be nervous." Kate thought it best to get it over with quickly moved into action removing her blazer, but Castle stopped her as she reached for the hem of her shirt. "Slower, Kate. I want to take the time to admire your body." He sat on the edge of the bed, and Kate apologized for her mistake.

"I'm sorry, Sir."

"You learn quickly, my dear. I appreciate that. Continue."

Kate lifted the shirt above her head, taking care to neatly place it at the foot of the bed. Castle made no move to touch her, admiring her from afar, and directed her to continue with her pants next. As her pants came off, she was left standing before her lover in her matching bra and panties and the heels she hadn't bothered to take off, a vision of the night clad in cherry red. She reached for the clasp of her bra, but Castle stopped her.

"Leave it on. I'll take it off when I'm ready. Come here and kneel by the bed." Kate obeyed quickly and stared up at her master, who dropped his pants to his ankles and revealed his erection. "I'm going to fuck your face, Kate. This is for my pleasure and mine alone, and you will not come until I tell you to, do you understand?" Kate nodded, but Castle pulled her hair and commanded her to speak.

"Yes."

"Yes, what?" He tugged harder and forced her eyes to meet his own, dark and hazy, swirling with lust.

"Yes, Sir." Castle hummed his pleasure and placed his cock in front of Kate's mouth. She opened, wrapped her lips around the base, and swirled her tongue around the tip, fully intent on pleasing her lover, but Castle had other ideas in mind. His left hand still in Kate's hair, he began to pump into her mouth, forcing her to stop her motions that countered his own, and fulfilled his earlier statement about fucking her face.

Kate could drink herself to death on the taste of Castle's cock in her mouth. He filled every crevice of her mouth, and even though he was using her for his pleasure, she couldn't help but enjoy listening to him groan in ecstasy. So, she did the instinctive thing for Kate, closed her eyes, and touched herself. She kept climbing higher and higher towards her peak and rubbed her clit while thrusting her fingers inside herself, though her fingers paled in comparison to Castle's.

Hopefully, Castle would be too focused on his nearing orgasm and wouldn't notice what her hands were doing, but she got lost in her own pleasure and carelessly let a moan slip from her lips that made Castle draw his attention to the woman below him with a hand on her breast and the other in her panties. Castle, outraged at her display, pulled out of her mouth and yanked her hair again.

"And just what do you think you're doing down there? I guess you didn't understand me when I said that this was for _my_ pleasure only. Did you come?" Kate said nothing, but she felt that sensation of her walls fluttering around her fingers more than once and knew she had disobeyed him and hung her head in shame. Her whimper was all he needed to know to answer his question. "You know what this means, right? Now I have no choice but to punish you."

"Please, Sir, I'm sorry. I'll be good. I—"

"You should have thought before you disobeyed me, Kate. I was very clear in my instruction, you chose to ignore me, and now you have to suffer the consequences. On the bed, hands and knees." Kate once again tried to apologize even as she followed his command, but Castle grabbed her roughly and pulled her back against his now shirtless chest to whisper in her ear. "Don't make me gag you." _Shit. Why the hell was this so arousing?_ Castle made a threat like that when he was joking about clamping her with salad tongs, but he turned it into something so sensual on a dime, and Kate found herself helpless to resist. "That's what I thought."

Castle placed Kate where he wanted her on the bed and took a moment to stare at her before removing her bra and tossing it aside. Though she couldn't see him, she felt his hungry eyes burning through her skin and piercing her soul, holding her captive to his will without the presence of chains. Slowly, Castle dragged his shortly clipped nails down her bare spine and pulled her panties down her legs, leaving them around her ankles. Kate's ass was now on display for Castle, and he forced her to turn back around when she attempted to sneak a glance at him. She felt at ease as he fondled her cheeks in his hands and massaged them in his palms . . .

Then came the first slap. It didn't hurt, really, but it caught her off guard to say the least, and she let out a gasp for air. He slapped her ass harder as a test the next two times in succession, and she moaned in pleasure, though trying to squirm away from the sting his touch left.

"Don't move, or I'll spank you harder." Kate forced herself to take her punishment statically as much as it disappointed her that she couldn't resist him, though, in that moment, she thought it would be more fun to do so. As he slapped her ass again, she made an effort to move away just to push his buttons; she did exactly that. Castle pinned her on her stomach and pulled her hands behind her, tying them together deftly. He kept his watch on her the whole time to make sure she was okay, but he noticed a change in her breathing and her hips grinding into the bedspread beneath her. And then he remembered her note.

" _There's a very fine line between_ _ **pleasure**_ _and_ _ **pain**_ _. They are two sides of the same coin, one not existing without the other."_

He finally understood the underlined sections of the contract in the book because he realized what it did to her. Castle knew what he needed to do to truly satisfy her desire, and now it was his time to use his leverage and give her what she asked for.

"So, you want me to spank you harder? Is that right, Kate?" She nodded into the soft mattress below her, but Castle wouldn't take that answer as sufficient, so he pulled her upright and bit along the edge of her ear. "Tell me. Say it out loud."

"Please spank me harder." Castle, knowing its sensitivity, pinched her breast roughly and grabbed her nipple between his fingers, twisting it sharply and toeing the very fine line. Kate's voice cracked on what would have been a scream but turned into a strangled cry instead.

"Begging won't do you any good if you don't address me properly. Now, tell me that correctly, and I make the pain go away." Kate struggled to find her voice in the moment but forced the words out for her own sake.

"Please spank me harder, _Sir_." Castle released her breast and gave the slightest laugh in her ear because he knew how much power he held over her in the moment, and he embraced it.

"Much better." Castle slapped her ass and the backs of her thighs harder than before and asked her if she wanted more or harder, and he drank in Kate's ethereal moans and pleas. He talked dirty to her, a kink he knew she was particularly fond of, commenting on the perfect roundness of her ass and how much he loved turning it pink under his hands. Kate expressed her content on a sigh dripping with sex and a string of continuous noise.

Just for fun, he slipped his hand down to her folds and found her dripping with heat, dampness staining the insides of her thighs. He rubbed her clit to bring her closer to her orgasm but left her hanging just before she could climax.

"You're really getting off on this, aren't you? Except for the fact that I ordered you not to come. You did anyway, I see. Since you just couldn't wait to release yourself, I'm going to make you wait that much longer."

"No, don't make me wait, Cas—" He slapped her ass again, and Kate arched her back in pleasure and curled her fingers into fists inside her cuffs. "Sir."

"Good girls get rewarded, bad girls get punished, and you, Katherine Beckett, deserve your punishment."

Castle released her from the tie but held her wrists together as he flipped her onto her back and pinned her hands above her head, smirking down at the woman at his mercy. For the first time, she studied his face and saw the raw power inside of him, but her Castle, who currently lay dormant behind his eyes, would appear at any moment she chose to use her words. She was determined, however, to avoid saying them because she trusted him and because she really did want this, so she let him bind her in place with the ties at all four corners of the bed for her wrists and ankles. Castle knew how much Kate loved his ties on him, so he decided to put them on her, and hell, did she look incredible like that? Spread open and bound, she was helpless.

"You look stunning like this, Kate. I'll have to remember to have you like this more often. Be as vocal as you want, but don't you dare come. Understood?"

"Yes, Sir," she answered with a small nod of the head.

"Good girl," Castle remarked as he kissed his way down her body from her collarbone to her naval, intentionally passing up her breasts. He decided to punish her then and blew a cool stream of air directly onto her nipples, dragging the very tip of his tongue across the bud for a fraction of a second before pulling away and continuing his downward path. Castle knew all the right places to stimulate Kate and how to keep her on edge longer, and he relished in his power.

"Please," Kate begged softly as he dipped his tongue inside her naval and skirted his fingernails up her sides. She stared at him, eyes burning with desire, and writhed under his ghostly touch, eager for something more concrete.

"Please? Please, what?"

"Please, Sir," Kate begged more earnestly and arched into his touch, signaling what she wanted by the roll of her hips. Castle chuckled and pressed her hips down into the bed with his forearm and continued to tease her with his lips.

"Well, since you asked me so politely, I am more willing to give you a reward, but your punishment still stands. Are we clear?" Kate responded correctly, and Castle rewarded her for her compliance by dragging his tongue through her folds, lapping up the wet sweetness already there. She tried to push her hips further onto his tongue, but his arm held her fast, and she had to take what he would give her. He rolled her clit between his teeth, the direct stimulation nearly making her leap off of the bed, and no matter how she tried to evade his touch or close her legs, she was forced to stay held open at the mercy of the man between her legs.

"Don't you dare," Castle warned as he felt Kate getting closer to reaching her climax. He made her hold off as her punishment for touching herself earlier, but he doubled her agony by not allowing her to touch him either. Kate cried out in frustration and did anything in her power, or lack thereof, to orgasm.

"God, I can't take it! Please—" Out of the blue, he slapped her pussy, and she arched her back on a broken scream. She was so close but never close enough. The overstimulation nearly killed her, and Castle forced her to open her eyes to keep her with him.

"Breathe. Breathe, Kate." Castle stopped touching her except for a sweep of her sweaty bangs behind her ear and a brush of a sweat bead from her forehead. Kate finally saw Castle when she came down from the near-orgasmic haze behind her eyes and evilly cursed whoever gave Castle the idea to make her wait to come. She took in a gasping breath for air and relaxed into the soft bed as Castle eyed her over to make sure she was okay. "Are you okay?" Kate nodded, and he kissed her forehead before continuing to pleasure her.

This time, he finally lavished her breasts like the rest of her glorious body and greedily took one in his mouth while stimulating the other with his hand. One of his hands filled her breast perfectly, but he focused on her nipple while he sucked the other breast in his mouth. Kate loved when Castle played with her like this, and her heightened sensitivity at the time made the experience all the more pleasurable. Her eyes rolled back in ecstasy as he hit a particularly sensitive nerve, letting go of any care she might have had.

Carefully, he inserted a finger deep inside of her, and she moaned at the intrusion and pushed against his finger. Castle knew exactly where and how to touch her so she could reach her peak, so he pushed her towards it faster and faster, her breathy moans increasing in pitch as she felt herself nearing the end. Kate's walls squeezed Castle's finger, and the sensation of having her breasts played with at the same time only stroked her fire even more. She could taste the sweet release on the tip of her tongue, just about ready to shout his name in pleasure . . .

He removed himself completely from her. Kate groaned and fought against the restraints keeping her from hitting Castle, and he chuckled at her attempts to break free, despite her pleas for release.

"Oh, Kate, we're just getting started."


	3. Chapter 3

Are You Curious?

Sprawled naked beneath him, Kate breathed heavily after her lover denied her release a second time and gave a last frustrated squirm before plopping her head on the pillow under her.

"I've got a surprise for you," Castle whispered, his voice gravelly and irresistible. Kate's inner muscles clenched around nothing, and she moaned at the loss of his body heat when he stood up from the bed and disappeared into the closet. He came back moments later with a black box tied with a red ribbon in hand, but this was no ordinary box . . . It was _her_ little black box, a cavern of wondrous, pleasurable treasures inside. Castle made a show of removing the ribbon, looping it around his wrist, and opening the lid, but he would not let Kate see what he was searching for. Judging from his lack of confusion at the items inside the box, Kate discerned that Castle had been through the box prior to now and was leading Kate on for show.

Castle pulled out his grey silk tie from the box that Kate had left for him to find earlier and moved to Kate's left side on the bed. Kate wasn't exactly sure of his plan for the item but trusted him enough to let him continue.

"Is this what you want?" Kate studied Castle and the tie for a brief moment before smiling slightly and batting her eyes.

"Yes, please."

"Close your eyes," he commanded softly, and Kate immediately obeyed. With her eyes closed, she could only hear Castle shuffling around and her ragged, aroused breathing. Kate felt her head being lifted up, and the silk wrapped tightly around her head, preventing her eyes from seeing. He had blindfolded her, and she knew at this point there was really nothing she could do. It put her at a serious disadvantage because she didn't know what to expect next, but Kate was sure she would enjoy the thrill.

She heard Castle rummaging through the box for something else, breathing a sigh of relief when he found the item he was looking for. Kate knew the object was metal because of the clank it produced when he pulled it from the box and held it in is palm. Obviously, it would be an object of punishment for Kate, and by knowing her weaknesses, she could exact that sweet revenge effortlessly. Kate tensed up on the bed when Castle's weight shifted the mattress and settled on top of her. He calmed her, slowly tracing the curve of her jaw and running his fingers through her hair, and she thankfully relaxed into the bed.

Suddenly, all she could feel was pain. Something clamped down on her, and Kate tried to move away from the pressure but was blocked by Castle's firm grip. A second pinch happened directly across from the first, and Kate knew then what the mystery object was.

"Nipple clamps," Kate breathed roughly.

"Very good, sweetheart. I'm going to leave these on for a while and make them nice and hard for me." Kate let out a high-pitched squeak as Castle tugged on the chain hanging in the valley of her breasts, and he moved lower on Kate's body to continue his torturous pleasure.

"Sir, please," she begged. Castle, of course, didn't stop his teasing kisses along Kate's stomach and lower.

"What do you want, Kate?" Though she couldn't see him, Kate felt his gaze burning through the blindfold and deep into her soul. This was more than just this moment; he wanted to know what she _really_ wanted.

"You. I just want you . . . Sir." His title, of course, was an afterthought of the line she had repeated from three short years ago. Castle hummed and kissed the flesh of her hipbone, another of Kate's most sensitive areas.

"Kate. Do you trust me?" This was her Castle, whose words flowed in genuine concern for his lover, slipping out of his role even if only for a moment.

"Always." And that cleared every doubt he could have had in his mind and washed away the uncertainty. It was their term for "I love you" in years past, but she used it again to answer him and affirm her faith in him and love for him.

With that, Castle continued to explore the treasure spread out before him, placing a pillow under her hips for a new angle. He dove straight for her clit without warning, and Kate cried out in pleasure, wishing desperately that she could curl her fingers into Castle's hair instead of her sweating palms. Castle took away his mouth for a split second before returning to delve his tongue inside of her and making an advance with his finger to trace around the rim of her ass.

Kate gasped. While they had played with the idea of anal and had indulged in it only once, it shocked her that Castle would be bold enough to make that move. Having her unable to see only made her senses more heightened, and the hairs on her arms stood up as Castle's touch sent erotic tremors through her body.

As gently as he could, he inserted his finger inside of her ass, and Kate arched into and away from him at the same time as he stretched the tight ring of muscle, an act that straddled the lines of pain and pleasure. Kate adjusted to the finger inside of her for a minute and clenched around it when the pleasure kicked in, urging him to thrust while making small noises of pleasure. If that was the reaction he got from one finger, then he could only wonder what he would get from his cock. He growled at the fantasy that played through his head, and he started moving inside of her.

"Let me hear you, Kate. There's no need to hold back. It's not like anyone else is here, though I know you would love it if they were. You want to be bad. You want to get caught. You want everyone to hear you screaming my name while I'm fucking you long and hard, don't you?"

"God . . . yes." Kate couldn't stop herself from being vocal at this point and allowed herself to do what she truly wanted and felt. Castle absolutely adored her when she begged him and let out her pleasures almost too loudly, and he smiled to himself as he saw her face contorted in ecstasy because he knew he was doing something right.

He switched to his thumb after a while and lathered it with lube before nudging her ass with it. Castle checked on her periodically, and her content moans and sobs of pleasure gave him the green light to continue, adding more fingers as he moved along. He had his fun playing with her and teasing her for some time, but his writhing and moaning lover beneath him didn't help his growing erection from becoming any less painful. So, he removed his touch from her and crawled up her body, untying the tear-stained blindfold from around her head and released her from all of the bonds keeping her to the bed. Castle turned her over and rubbed her pink cheeks from his recent treatment and tested Kate's readiness for his cock a final time.

"Now, I'm going to fuck your ass, Kate. Would you enjoy that? Having my cock disappear inside you, filling you up entirely." Kate hummed low in her throat in appreciation at Castle's filthy mouth that she loved when he used in bed. "That's right, you dirty girl. You _love_ it." He slid on a condom before he aligned himself to her ass and slowly pushed the head of his cock into her. The fantasy was much more pleasant than the reality. She resisted the intrusion at first and whimpered as he attempted to push more of him into her, so Castle stroked her curves and up her ribs with his nails, shushing her pitiful cries. "It'll only take a second, but I'm gonna push all the way in. Just relax for me, baby."

Kate's eyes fluttered as his touch sparked her abandoned clit back to life and made her immediately fall into a state of bliss. This was his short window to take the final plunge, and while Kate's head was thrown back in pleasure, Castle filled her ass to the hilt and forced himself to hold there for Kate's sake. She didn't cry out like Castle thought she would, but her muscles gripped him almost too tightly from the sensation, and she desperately wished she could cling to her lover's shoulders and draw her nails against his back. Once again, her nails the flesh of her own palms was the only thing keeping her on solid ground.

It was almost like he could read her mind though because, all of a sudden, Kate almost plopped onto the bed, and it didn't register that Castle had granted her wish until Castle hooked one of her arms around his neck for leverage. He started to lightly thrust, barely even moving, and Kate grabbed his shoulders fiercely and dug her nails into the ridges of muscle there while gripping the bedsheets for dear life with her other hand. Between the clamps and the cock filling her ass, Kate wasn't sure how much more she could take. Something had to give, and hopefully, Castle understood that. The pressure in her nipples was lifted slowly, and Kate breathed a sigh of relief.

"Thank you, Sir." Breathily, Kate offered her appreciation for the gift Castle had just provided for her, though he still kept thrusting into her.

"It's only because I don't want you to come yet. Not until I'm deep inside your pussy, and that won't happen until you've earned it. So, Kate, this begs the question." Castle leaned over her and drew the shell of her ear into his mouth as he teased her with his question. "Have you earned it?" Kate's next breath out shuddered against her chest, and she blinked rapidly, her brown eyes rolled into the back of her head.

"I think so. Y—yes, Sir," Kate shakily forced out. She was rewarded with a deep thrust in her ass that made him latch his teeth into her pulse point, and Kate fisted her hand in his hair as she threw her head back.

"That's a good girl," Castle hummed and pulled out of her delicately. He reached down to pull the condom off, and he turned Kate on her back to face him once again because now he wanted her all over him, clinging to him as he fucked her into blissful oblivion. "Now, you're going to come. You're going to come until you're a slave to it, until you can do nothing but come for me over and _over_ and _**over**_ again. Don't think about it, Kate. Just let go."

When he pushed into her, it didn't take long for Kate's body to respond and squeeze her inner muscles around his thick cock. Castle held himself back from releasing until the last possible moment, but his self-control was ripping at the seams with his muse beneath him doing nothing but releasing herself for him. It was all for him, for his pleasure, because she always aimed to please.

For the first time that night, the couple kissed. Though the kisses weren't sweet and adoring, they were what they both desired in the moment. Lips found each other in tangled hurried duels for power, tongues tasting each other and drinking the lust swirling in their mouths. Their teeth clacked together a few times in their animalistic but passionate display of need for one another, and when their lips weren't fused together, Castle encouraged Kate to come with his dirty words. One right after the other, Kate came hard around Castle, pushing and pulling against him to achieve her ultimate release, and Castle didn't stop. He let Kate take her pleasure from him because he knew how long he had denied her orgasm and pitied her.

He lost count long ago of how many times Kate clamped down around him and screamed his name in ecstasy, but he couldn't get enough of seeing his lover with her head thrown back and skin flushed as he brought her over the edge time and time again. Castle was quickly losing his ability to hold off, but he kept going for her as long as he could. In the next moment, Kate came hard enough to make her squirt, and that's what did it for Castle. The force of her release triggered his own, and Castle spilled himself inside of Kate in long spurts, filling her up as deeply as he could.

Sensation swirled around her eyes, and her biggest release yet made her lose all rationality for a few moments. Kate clung to Castle as if her life depended on it, arms wound around his neck, lithe legs twined around his hips, and kiss-swollen lips gripped his neck. This release took her to another dimension where only she and her lover existed in unadulterated sexual nirvana, and a release like that was one that only he, her true love, could give her. Kate felt like she could fly with him, so she soared above the clouds and declared her love for Castle on broken screams long into the night.

The first thing Kate felt when she returned to Earth was water. She was partially reclining in it, so she assumed that she was in the bath. A hand stroked her shoulder, and she relaxed into Castle's familiar form behind her as he reached up and scooped water into his palm and ran it down her arm to rinse off the vanilla-scented body wash. He kissed the juncture of her neck and shoulder softly and leaned her back against his chest.

"Did you enjoy that, love?" Kate nodded and smiled as she rested her head in the crook of his shoulder and allowed him to take care of her. She really could get used to this, being loved completely by this wonderful man, and Kate sighed sweetly as Castle wrapped his strong and loving arms around her waist, holding her close.

"I love you, Rick." She turned in his arms to face him and gave him a tender kiss to express it.

"And I love you, Kate. You know you can tell me anything, right?" She nodded and wondered what possible information he might want to know, and it hit her.

"You want to know about the book." Castle stared at her like she was a genius for figuring out his intent, and Kate smiled at him. "You were _not asking_ very loudly." Castle looked away nervously and wrung his hands together behind Kate's back.

"I just . . . was it something that I wasn't doing? Something I wasn't giving you? Because if it was, I—"

"Castle," Kate hushed him with two fingers on his lips. "It's not that at all, I promise. I had always been curious about what it would be like to experience that. You know, total submission and all. I guess I was just too scared to ask for some reason. Well, I thought you might think that I was weird or something. It's stupid, I know." Castle kissed her, ending her babbling.

"Not stupid, Kate. Human. It's okay to have fantasies. You know I do." Kate rolled her eyes when he crooked an eyebrow at her but smiled. "Don't be afraid to tell me these things, okay? I won't think you're weird. I mean, hell, I married you of all people, didn't I?"

"More like I married _you_ ," Kate scoffed playfully, and he kissed her again with the same sweetness and love as before. Castle unplugged the bathtub drain and helped Kate to stand, drying her off with a towel. "Okay, so I was reading about this one position that—"

"Kate, aren't you exhausted?" The concern in his eyes warmed her heart secretly, but she played off the flirty need to his face.

"What's wrong, Castle? Not scared of a little _action_ , are you?" Castle dropped the towel from around Kate's body and lifted her onto the cool granite of the bathroom counter. He growled and kissed her passionately again.

"Action is my middle name."


End file.
